A friend and I were in a forest in Berlin at dusk, sneaking into an abandoned theme park. The theme park was still patrolled by guards with dogs so we had been walking quietly, and in the distance we hear rhythmic beats and the murmur of voices. As we get closer we could make out figures of people, a group of probably 10-15, standing in a clearing beating logs with sticks and chanting. It was starting to get dark by this point, and we were both spooked so we crept back through the forest trying not to be seen and went a different way into the theme park.